The Effects of Fire and Mechanical Fuel Treatments on Wildlife in the Mixed-conifer Forest of the Sierra Nevada PDF Download
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Author: Andrew James Amacher
Publisher:
ISBN: 9780549164920
Category :
Languages : en
Pages : 316
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Book Description
For avian foraging, all 9 species examined exhibited significant selectively for certain tree species within pre- or post-treatment periods. Four species exhibited a significant positive shift to California black oak from pre- to post-treatment periods in both burned and unburned stands. For most species, selectivity was generally consistent with previously published work within similar forest types.
Author: Andrew James Amacher
Publisher:
ISBN: 9780549164920
Category :
Languages : en
Pages : 316
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Book Description
For avian foraging, all 9 species examined exhibited significant selectively for certain tree species within pre- or post-treatment periods. Four species exhibited a significant positive shift to California black oak from pre- to post-treatment periods in both burned and unburned stands. For most species, selectivity was generally consistent with previously published work within similar forest types.
Author: Andrew James Amacher
Publisher:
ISBN:
Category : Animals
Languages : en
Pages : 158
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Book Description
Author: Michelle Erin Monroe
Publisher:
ISBN:
Category : Chipmunks
Languages : en
Pages : 278
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Book Description
"Prescribed fire is an important management practice used to restore natural fire regimes in Sierra Nevada mixed conifer forests where fire has been suppressed over the last century. It is not well known, however, how the timing of prescribed fire affects wildlife species. I compared the effects of prescribed fires during the early season (spring and early summer) with those during the late season (late summer and fall) on small mammal populations using model selection and inference methods. ... Lodgepole chipmunk (Neotamias speciosus) movements differed between years, but there was no effect of prescribed fires on their movements (Chapter 1). Deer mouse (Peromyscus maniculatus) movements differed between age groups within years. Prescribed fire treatments did not affect deer mouse movements, except when only adult female deer mouse movements were analyzed. Year effects were more important than fire effects on lodgepole chipmunk densities, total small mammal biomass, deer mouse densities, and deer mouse age ratios (Chapter 2). Prescribed burning had a positive effect on deer mouse pregnancy ratios, and there was only limited support for an effect of year on these ratios. There was essentially no support for different effects of fire depending on the season of fire on total small mammal biomass and deer mouse densities, and only limited support for these effects on lodgepole chipmunk densities, deer mouse age ratios, and deer mouse pregnancy ratios. The prescribed fire treatments differentially impacted small mammal habitat components depending on the season of the fire (Chapter 3). However, there were few significant relationships between these habitat components and deer mouse densities, lodgepole chipmunk densities or small mammal species richness. Overall, year effects often had the greatest influence on the small mammal populations examined, and there were few strong differences between the effects of early season fires and late season fires on these populations."--Abstract.
Author: Leda Nikola Kobziar
Publisher:
ISBN:
Category : Forest fires
Languages : en
Pages : 416
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Book Description
"Throughout fire-adapted forests of the western US, and in the Sierra Nevada of California specifically, wildfire suppression has produced forest structures conducive to more severe, costly, and ecologically deleterious fires. Recent legislation has identified the necessity of management practices that manipulate forests towards less fire-hazardous structures. In the approximately 30 year old pine plantations of the Stanislaus National Forest, extensive fuels reduction procedures are being implemented. This dissertation addresses whether silvicultural and burning treatments are effective at reducing the intensity and severity of potential fire behavior, and how, along with wildfire, these treatments impact the evolution of carbon dioxide from the soil to the atmosphere. The first chapter addresses the relationships between soil respiration, tree injury, and forest floor characteristics in high and low severity wildfire burn sites in a salvage-logged mixed-conifer forest. The results indicate that fire severity influences soil CO2 efflux and should be considered in ecosystem carbon modeling. In the next chapter, fire models suggest that mechanical shredding of understory vegetation (mastication) is detrimental, and prescribed fire most effective in reducing potential fire behavior and severity in pine plantations. The third chapter documents the impact of alternative fuels treatments on soil carbon respiration patterns in the pine plantations, and shows that mastication produces short-term reductions in respiration rates and soil moisture. The final chapter further examines the relationships of fire-induced tree injuries, forest floor structure, and environmental factors to soil respiration response to fuels treatments. Each chapter is written as an independent manuscript; they collectively serve to expand the limited understanding of the effectiveness and ecological consequences of fire and fuels treatments in coniferous forests."--Abstract
Author: James D. McIver
Publisher:
ISBN:
Category : Forests and forestry
Languages : en
Pages : 222
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Book Description
Author: Lindsay Aney Chiono
Publisher:
ISBN:
Category :
Languages : en
Pages : 162
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Book Description
Historic fire regimes in the dry conifer forests of the southern Cascade and northern Sierra Nevada regions of California were characterized by relatively frequent fires of low and mixed severity. Human management practices since the mid-19th century have altered the disturbance role of fire in these dry yellow pine and mixed conifer forest ecosystems. Fire suppression, high-grade timber harvesting, and livestock grazing have reduced the frequency of burning and caused a shift in the structure and species composition of forest vegetation. These changes, including high levels of accumulated fuel and increased structural homogeneity and dominance of shade-tolerant tree species, combined with a warming climate, have rendered many stands susceptible to high-severity fire. In many forests of the western United States, wildfires are increasingly difficult and costly to control, and human communities are regularly threatened during the fire season. Treating wildland fuels to reduce wildfire hazards has become a primary focus of contemporary forest management, particularly in the wildland-urban interface. The specific objectives of treatment are diverse, but in general, treatments address accumulated surface fuels, the fuel ladders that carry fire into the forest canopy, and surface and canopy fuel continuity. These modifications to forest fuels can alleviate the severity of a future wildfire and support suppression activities through improved access and reduced fire intensity. While fuel reduction treatments are increasingly common in western forests, the long-term structural and ecological effects of treatment remain poorly understood. This dissertation uses a chronosequence of treated stands to examine the temporal influence of treatment on forest structure, the understory plant community, and wildfire hazard. The first chapter examines the effects of fuels reduction treatment on stand structure, overstory species composition, and ground and surface fuels. The stand structures and reduced surface fuel loads created by fuels modification are temporary, yet few studies have assessed the lifespan of treatment effects. The structural legacies of treatment were still present in the oldest treatment sites. Treatments reduced site occupancy (stand density and basal area) and increased quadratic mean diameter by approximately 50%. The contribution of shade-tolerant true firs to stand density was also reduced by treatment. Other stand characteristics, particularly timelag fuel loads, seedling density, and shrub cover, exhibited substantial variability, and differences between treatment age classes and between treatment and control groups were not statistically significant. The second chapter evaluates fuel treatment longevity based on potential wildfire behavior and effects on vegetation. Forest managers must divide scarce resources between fuel treatment maintenance, which is necessary to retain low hazard conditions in treated stands, and the construction of new treatments. Yet the most basic questions concerning the lifespan of treatment effectiveness have rarely been engaged in the literature. In this study, field-gathered fuels and vegetation data were used to aid fuel model selection and to parameterize a fire behavior and effects model, Fuels Management Analyst Plus. In addition, a semi-qualitative, semi-quantitative protocol was applied to assess ladder fuel hazard in field sampling plots. Untreated sites exhibited fire behavior that would challenge wildfire suppression efforts, and projected overstory mortality was considerable. In contrast, estimated fire behavior and severity were low to moderate in even the oldest fuel treatments, those sampled 8-26 years after treatment implementation. Findings indicate that in the forest types characteristic of the northern Sierra Nevada and southern Cascades, treatments for wildfire hazard reduction retain their effectiveness for more than 10-15 years and possibly beyond a quarter century. Fuel treatment activities disturb the forest floor, increase resource availability, and may introduce non-native plant propagules to forest stands. Non-native plant invasions can have profound consequences for ecosystem structure and function. For these reasons, there is concern that treatment for fire hazard reduction may promote invasion by exotic species. Several short-term studies have shown small increases in non-native abundance as a result of treatment, but the long-term effects have rarely been addressed in the literature. The final chapter examines treatment effects on the understory plant community and on cover of the forest floor, as mineral soil exposure has been linked to invasion. Regression tree analysis provided insights into the influence of treatment and site characteristics on these variables. Treatments increased forb and graminoid cover, but temporal trends in abundance were opposite. An initial increase in forb cover in the most recently treated sites was followed by a gradual decline, while mean graminoid cover was highest in the oldest treatments. Shrubs dominated live plant abundance. Shrub cover showed few temporal trends, but was negatively associated with canopy cover. Mineral soil exposure was increased by treatment and declined slowly over time, remaining elevated in the oldest treatments. Non-native plant species were very rare in the treatment sites sampled in this study. Despite the availability of bare mineral soil and the proximity of transportation corridors, a source of non-native propagules, non-natives were recorded in only 2% of sampling plots. This study suggests that forest disturbance associated with treatment for hazardous fuels reduction may not produce significant invasions in these forest types.
Author: Emily Eleanor Yukie Moghaddas
Publisher:
ISBN:
Category :
Languages : en
Pages : 316
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Book Description
Author: Jens Turner Stevens
Publisher:
ISBN: 9781321213010
Category :
Languages : en
Pages :
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Book Description
Montane coniferous forests in western North America are experiencing rapid environmental change, due in part to increasing fire severity and decreasing winter snowpack. Many of these forests experienced frequent low-severity fires prior to intensive logging and fire suppression during the nineteenth and twentieth centuries, which have led to increased fuel loads and increased dominance by fire-sensitive, shade-tolerant tree species. Forest managers seeking to mitigate increases in fire size and severity are increasingly implementing fuel-reduction treatments, which target small trees and surface fuels for removal. However, the ecological effects of these treatments on subsequent wildfire behavior, forest resilience, understory plant community dynamics, and plant invasions have not been well documented. In Chapter 1, I utilized a large-scale natural experiment to investigate the effects of recent fuel treatments on subsequent wildfire severity and structural resilience, in twelve different yellow pine and mixed-conifer forest sites in the mountains of eastern California. By quantifying forest structure in treated and adjacent untreated stands, both after wildfire and without wildfire, I demonstrated that treatments reduced the amount of structural change caused by wildfire, as a result of their moderating effect on fire severity. Two years post-wildfire, treated stands resembled pre-wildfire stands, in that they had greater tree litter cover, more tree seedling regeneration, less shrub cover and recruitment, and less bare soil relative to untreated stands, which generally burned at very high severity. In Chapter 2, I used the same network of twelve sites to test whether the gradient of disturbance severity, from untreated and unburned stands to high-severity wildfire stands, generated predictable patterns of understory plant community composition and diversity. I incorporated information on the evolutionary history of the native flora to show that increasing disturbance severity favored understory species with southern biogeographic affinity. Analysis of leaf functional traits indicated that increases in microclimatic water deficit in high-severity stands favored species with reduced specific leaf area relative to their leaf Nitrogen concentration. Native plant diversity at the stand scale was greatest in treated stands that subsequently burned in a wildfire, however this diversity peak was due to increased plot-scale alpha diversity relative to undisturbed stands, and increased between-plot beta diversity relative to high-severity wildfire stands. Conversely, exotic plant diversity peaked in high-severity wildfire stands that had not been previously treated. In Chapter 3, I investigated the population-level response of non-native species to interactions between forest harvesting strategies, prescribed fire, and winter snowpack depth using a transplant experiment with two non-native shrubs: Scotch broom (Cytisus scoparius L. (Link)) and Spanish broom (Spartium junceum L.). Both species had the strongest positive population growth responses to canopy thinning, rather than clearcuts or dense canopies. Despite positive effects of prescribed fire on seed germination, frequent prescribed fire was shown to decrease population growth rates for both species. However, experimental snowpack reductions led to increased winter survival by both species, which translated into strong positive effects on population growth rates. Under a future climate scenario where winter snowpack levels increase in elevation, middle-elevation forests that experience fuel treatments may therefore be at increased risk of invasion by non-native plants due to synergies between climate and management regimes.
Author: David S. Pilliod
Publisher:
ISBN:
Category : Forest animals
Languages : en
Pages : 44
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Book Description
This paper synthesizes available information on the effects of hazardous fuel reduction treatments on terrestrial wildlife and invertebrates in dry coniferous forest types in the West. We focused on thinning and/or prescribed fire studies in ponderosa pine (Pinus ponderosa) and dry-type Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), and mixed coniferous forests. Overall, there are tremendous gaps in information needed to evaluate the effects of fuel reduction on the majority of species found in our focal area. Differences among studies in location, fuel treatment type and size, and pre- and post-treatment habitat conditions resulted in variability in species responses. In other words, a species may respond positively to fuel reduction in one situation and negatively in another. Despite these issues, a few patterns did emerge from this synthesis. In general, fire-dependent species, species preferring open habitats, and species that are associated with early successional vegetation or that consume seeds and fruit appear to benefit from fuel reduction activities. In contrast, species that prefer closed-canopy forests or dense understory, and species that are closely associated with those habitat elements that may be removed or consumed by fuel reductions, will likely be negatively affected by fuel reductions. Some habitat loss may persist for only a few months or a few years, such as understory vegetation and litter that recover quickly. The loss of large-diameter snags and down wood, which are important habitat elements for many wildlife and invertebrate species, may take decades to recover and thus represent some of the most important habitat elements to conserve during fuel reduction treatments. Management activities that consider the retention of habitat structures (such as snags, down wood, and refugia of untreated stands) may increase habitat heterogeneity and may benefit the greatest number of species in the long run.
Author: Nick A. Littlewood
Publisher: Open Book Publishers
ISBN: 1800640862
Category : Nature
Languages : en
Pages : 714
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Book Description
Terrestrial Mammal Conservation provides a thorough summary of the available scientific evidence of what is known, or not known, about the effectiveness of all of the conservation actions for wild terrestrial mammals across the world (excluding bats and primates, which are covered in separate synopses). Actions are organized into categories based on the International Union for Conservation of Nature classifications of direct threats and conservation actions. Over the course of fifteen chapters, the authors consider interventions as wide ranging as creating uncultivated margins around fields, prescribed burning, setting hunting quotas and removing non-native mammals. This book is written in an accessible style and is designed to be an invaluable resource for anyone concerned with the practical conservation of terrestrial mammals. The authors consulted an international group of terrestrial mammal experts and conservationists to produce this synopsis. Funding was provided by the MAVA Foundation, Arcadia and National Geographic Big Cats Initiative. Terrestrial Mammal Conservation is the seventeenth publication in the Conservation Evidence Series, linked to the online resource www.ConservationEvidence.com. Conservation Evidence Synopses are designed to promote a more evidence-based approach to biodiversity conservation. Others in the series include Bat Conservation, Primate Conservation, Bird Conservation and Forest Conservation and more are in preparation. Expert assessment of the evidence summarised within synopses is provided online and within the annual publication What Works in Conservation.
